Poly(Rhodamine B) modified carbon paste electrode for the selective detection of dopamine

An electrochemical sensor for the selective detection of dopamine was developed by the electropolymerization of Rhodamine B dye at a carbon paste electrode. Under physiological conditions, the modified electrode was able to resolve the voltammetric peak of dopamine from all interfering species whose concentrations were thousand folds more than that of dopamine. A wide linear dynamic range of 6–1000 μM and a detection limit of 3.99 × 10− 6 M were observed for dopamine. The main advantage of the modified electrode using differential pulse voltammetric technique is its inability to sense the presence of micro-molar levels of ascorbic acid and uric acid while it can detect dopamine at the micro-molar level. This unique property of the modified electrode eliminates the possible interferences of low concentrations of ascorbic acid while also making it more sensitive and convenient to use as a sensor for the detection of low concentrations of dopamine in real samples. Satisfactory results were obtained while the modified electrode was employed for determination of dopamine in human blood serum and dopamine hydrochloride injection. The electrode showed excellent reproducibility, selectivity and antifouling effects.